Heterogeneous β-Co(OH)2/Cu2(OH)3Cl bifunctional electrocatalyst for superior concurrent conversion of glycerol and nitrite

Abstract

The electrochemical biomass valorization of industrial by-products or pollutants using renewable electricity offers significant promise for carbon neutrality. However, the huge challenges still exist in the development of efficient bifunctional electrocatalysts. Herein, we put forward a high-efficiency co-electrolysis system by coupling the nitrite reduction reaction (NO₂RR) and the glycerol oxidation reaction (GOR) over a novel heterogeneous β-Co(OH)₂/Cu₂(OH)₃Cl catalyst. The β-Co(OH)₂/Cu₂(OH)₃Cl shows excellent bifunctional performance with high Faradaic efficiencies of formate (90.1%) and NH₃ (91.9%) at cell voltage of 1.5 V, high yield rate of formate (89.6 mg h⁻¹ cm⁻²) and NH₃ (36.07 mg h⁻¹ cm⁻²) at cell voltage of 1.9 V, and superior stability in an anion exchange membrane co-electrolyzer. The in-situ Raman result confirms the unique Co/Cu-based bimetallic synergistic sites of β-Co(OH)₂/Cu₂(OH)₃Cl towards superior GOR performance, while the operando Fourier transform infrared spectroscopy demonstrates the improved protonation kinetics of key intermediates and optimized water dissociation ability of β-Co(OH)₂/Cu₂(OH)₃Cl for high NO₂RR activity. Our work illuminates alternative avenues to exploit the innovative and energy-saving technology for the co-production of high-added chemicals.